Capacidad de depredación y comportamiento de Alpaida veniliae (Araneae: Araneidae) en el cultivo de arroz

Abstract

Using the Ivlev index, the selectivity of A. veniliae on its prey species Conocephalus sp. (Tettigoniidae) and Hortensia similis (Cicadellidae) was established. Potential prey species were determined through visual censuses in transects. To establish the consumption rate/spider/day, ten spider webs were visually examined in the field, measuring the number of prey captured and the time used from prey capture to final consumption. Results showed that there was no selectivity towards Conocephalus sp. (Ivlev = 0.08), the most abundant prey in the crops and webs. For H. similis, the selectivity index was 0.92 indicating a marked preference. The consumption rate of A. veniliae on Conocephalus sp. was 7.7 prey/day and for H. similis 5.8 prey/day. From the ecological point of view, the predatory habits of A. veniliae could have strong implications for the regulation of populations of these two phytophagous species in mechanized dryland rice agroecosystems.